1. Field of the Invention
The present invention relates to a method and apparatus for detecting a molten metal surface level in a casting mold for a molten metal, particularly for a continuous casting apparatus.
2. Description of the Prior Art
Heretofore, it has been difficult to continuously detect a molten metal surface level in a casting mold in a continuous casting apparatus since the molten metal to be treated has a high temperature. As a solution to this difficulty, Japanese Patent Publication No. 42848/79 discloses a method in which an electrode is inserted in slag constituting a layer under flux floating on the surface of molten metal, detecting a change of electric resistance due to a temperature gradient of the location at which the electrode is inserted, wherein the electrode is displaced upwardly or downwardly to cause the detected value to be constant and the degree of displacement is measured.
Other than the above noted method, there have been proposed some techniques for detecting a molten metal surface level in a casting mold in a continuous casting apparatus in Japanese Laid-open Patent Application No. 122622/78, Japanese Patent Publication No. 49944/80 and Japanese Patent Publication No. 42846/79.
The present invention is concerned particularly with an improvement over the method for detecting a molten metal surface level in a mold as disclosed in Japanese Patent Publication No. 42848/79.